The present invention relates to the manufacture of beaded foam molded products and, more particularly, to an improvement in beaded foam molded board and the like which includes a vapor phase corrosion inhibitor useful in packaging and other applications.
Beaded foam molded products, as used herein, includes board, blocks and forms which are produced by molding expanded beads or prepuffs of polystyrene and its interpolymers and its alloys such as polystyrene/polyethylene, polypropylene and its interpolymers, and such other resins as may be developed for use in making such board, blocks and forms.
Vapor phase corrosion inhibitor agents presently can be found in stock packaging materials in several forms such as, for example, in polyethylene bags, extruded plastic sheeting or film, paperboard and paper wrapping. Alternatively, such agents can be provided in small canisters and other devices containing the inhibitor and permitting its vapors to emanate therefrom into the package enclosure in which placed. These devices are called emitters in that they emit the vapors of the corrosion inhibitor over time. In a like manner, such agents may be supplied within paper or fabric packets which are placed in the packages. Such packets usually take the form of an air permeable envelope in which is provided a corrosion inhibitor. An example of such a typical packet is disclosed in U.S. Pat. No. 4,973,448 issued to Carlson, et al. on Nov. 27, 1990. Here it is disclosed to fabricate the packets or envelopes using fabric material comprised preferably of an synthetic resin polymer material, such as polyethylene, and a powdered volatile corrosion inhibitor, such as an organic amine acid salt.
In lieu of such packets and or emitters, solid corrosion inhibitors, e.g. pills or tablets, may simply be placed into the packaging with the shipped item. In some instances, the product being placed in the container may be sprayed or otherwise coated with the corrosion inhibitor. For any of these items to work, the person responsible for packaging must remember to place the inhibitor into the container or on the product before shipping. In any event, these approaches involve added steps and costs and may not be effective for providing protection for extended period of time.
Hence, another approach to providing corrosion inhibiting material in packaging is disclosed in U.S. Pat. No. 5,320,778. In this patent, it is disclosed to incorporate the corrosion inhibitor in a foam material during the extruding process. The corrosion inhibitor used however is a vapor phase inhibitor-desiccant composite in which a granular cylocogell is used as the substrate onto which the vapor phase corrosion inhibiting component is deposited and this composite material is incorporated in the extrusion process.
Beaded foam plank, custom shapes or board and blocks are extensively used to provide support for and protect articles being shipped. Frequently, such blocks are configured to provide recesses which seat the articles, or the beads may be molded into custom shapes. Bags containing the corrosion inhibitor are included in packages utilizing such beaded foam board to cushion the contents.
In addition, there has been recognized a need to provide inert materials which would provide corrosion protection for metal structural elements in various structures and prior to use in construction.
Accordingly, it is an object of the present invention to provide a novel method for making a beaded foam molded product having a vapor phase corrosion inhibitor incorporated therein and which may be readily used for packaging a product which is susceptible to corrosion.
It is also an object of the invention to provide such a method wherein the corrosion inhibiting material is applied to the puffed foam beads in the course of the conventional process of manufacture.
Another object of the invention is to provide a novel beaded foam molded product containing a vapor phase corrosion inhibitor throughout.